The invention concerns a telescopic push-pull prop for the construction industry, comprising an outer tube and at least one threaded rod or inner tube, which is disposed in the outer tube such that it can be axially adjusted therein and an outer thread of which engages with an inner thread of the outer tube.
Push-pull props of this type are used in the building industry to align wall formworks for concrete walls and secure them against any possible wind loads or other transverse loads that might occur during construction operation.
At both of their ends, the push-pull props normally have threaded rods that engage with inner threads of the outer tube, which run in an opposite direction thereto. During operation, the threaded rod of one end is thereby tightened in a torque-proof fashion on a firm support, whereas the threaded rod at the other end of the push-pull prop engages with a formwork element or the like to be supported. The length of the push-pull prop is adjusted by corresponding rotation of the outer tube in relation to the rotationally fixed threaded rods.
The respective inner thread of the outer tube of these push-pull props is either produced by a threaded nut that is welded to the respective end of the outer tube, or by tapering the respective end and simultaneously impressing the thread, or by subsequent machining of the outer tube.
In view of the conditions of use of the push-pull props, the area of the inner thread is often soiled, e.g. by fresh concrete, which can result in malfunction or increased wear of the thread of the push-pull prop. In addition thereto, the mechanical load that cannot be prevented during operation sometimes directly damages the inner thread which can result in failure of the push-pull prop.
It is the underlying purpose of the invention to present a push-pull prop of this kind, which is better protected against soiling and damage and at the same time can be produced at low cost.